N-methyl-D-aspartate receptors (NMDAR) can regulate the intracellular calcium concentration of keratinocytes (KC) and seem to be important for their growth and differentiation. The objective of this study was to identify the subtype(s) of this receptor expressed by KC in vitro. The mRNA was isolated from primary cultures of KC as well as from a KC cell line (HaCaT) and expression of the NMDAR subtypes determined by using RT-PCR. At the mRNA level, we found expression of only the constant NMDAR1 as well as the subtype NMDAR2D. In contrast to the other subtypes of NMDAR, NMDAR2D is characterized by low influence of magnesium to the receptor function. This characteristic is consistent with previously published functional investigations in KC. The identification of the NMDAR2D subtype in KC may be of value for the development of new therapeutic approaches.